1005 Dial Type Thermometers

Precimeasure thermometer products for transformer temperature management and control cover every aspect of need and design for all sizes and configuration of transformer.


The basic power transformer OTI (Oil Temperature Indicator) and WTI (Winding Temperature Indicator) are identified by model numbers 1005 and 1005A. The winding temperature is calculated by fitting a heater coil around the low pressure top oil measuring bellows connected to the bulb in the tank. The heater coil current is a derivative of the load current.

These indicators offer local display and switching. A common stocked model is : 2 switch OIL, 4 switch WINDING, with 5 metre capillary … 1005/1005A thermometers


Early indicators only offered local display – developing systems of digital communication of mechanical information gave rise to electrical outputs within the thermometer case converting mechanical temperature measurement to resistance in ohms. A voltage supply to the instrument converted that resistance value (the Pt100 standard) to amps, the output available in Precimeasure models 1005AH … 1005H thermometer

Other indicators on the market deliver one Pt100 output through a rotating potentiometer fixed to the measuring mechanism behind the temperature display dial. In this case, if the measuring system loses pressure and fails to imitate the correct top oil or winding temperature, the SCADA output also measures that incorrect temperature.

However, the Precimeasure model 1005AH and model 1005AHX (with TWO Pt100 sensors embedded in the bulb still deliver a SCADA output independent of the mechanical reading … 1005AHX thermometer
Drawings and specifications : the ordering parameters are complex and Electric Systems reduces the complexity of the manufacturer’s specification to easily remembered and used model numbers.
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Type tests and model variations for 1005 Thermometers … 1005 ordering information